If the spring brakes are on, when should you push the brake pedal?

If the spring brakes are on, when should you push the brake pedal?

• A. never
• B. before starting the engine
• C. Only when in reverse
• D. When the parking brake is engaged

Answer: (A)

Spring brakes act as a parking brake in many air-brake trucks. When they’re on, the springs hold the brakes applied to keep the vehicle stationary, and they’re released only by applying air pressure to the brake chambers. The brake pedal, however, is for the service brakes used during normal driving after the parking brake has been released. If the spring brakes are on, pushing the brake pedal won’t help in releasing them and isn’t the way to control the vehicle. You should not press the pedal while the springs are engaged; instead, release the parking brake by applying air pressure, then use the service brakes as needed.

Spring brakes act as a parking brake in many air-brake trucks. When they’re on, the springs hold the brakes applied to keep the vehicle stationary, and they’re released only by applying air pressure to the brake chambers. The brake pedal, however, is for the service brakes used during normal driving after the parking brake has been released. If the spring brakes are on, pushing the brake pedal won’t help in releasing them and isn’t the way to control the vehicle. You should not press the pedal while the springs are engaged; instead, release the parking brake by applying air pressure, then use the service brakes as needed.